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Origin and Habitat: Orbea wissmanii is rather common in the highlands from Asir, Saudi Arabia to Dhofar, Oman and Yemen.
Type locality: Yemen. Pass between Jebel Shibam and Jebel Dhulwa 2400-2800 m
Altitude range: This species occurs at high elevations (c. 2000 m)
Habitat and ecology: This species grows on bare rocky slopes often among boulders or under Commiphora and Anisotes shrubs.
- Orbea wissmannii (O.Schwartz) Bruyns
Orbea wissmannii (O.Schwartz) Bruyns
Aloe 37(4): 76. 2000
- Orbea wissmannii (O.Schwartz) Bruyns
- Angolluma wissmannii (O.Schwartz) Plowes
- Caralluma wissmannii O.Schwartz
- Pachycymbium wissmannii (O.Schwartz) M.G.Gilbert
- Caralluma meintjesiana Lavranos
- Orbea wissmannii var. eremastrum (O.Schwartz) Bruyns
- Angolluma eremastrum (O.Schwartz) Plowes
- Caralluma eremastrum O.Schwartz
- Orbea wissmannii subs. eremastrum (O.Schwartz) Mosti & Raffaelli
- Pachycymbium eremastrum (O.Schwartz) M.G.Gilbert
- Orbea wissmannii var. parviloba Bruyns
Description: Orbea wissmanii (formerly known as Caralluma wissmannii or Angolluma wissmanii) is a low growing succulent species with erect four-angled stems 7 cm tall, these pale and dark green dappled and soft-toothed. It spreads over the ground forming large crowded, cushions up to 1 metre across. The flowers are five-pointed fleshy stars produced in late Summer or Autumn, they are variable in appearance and range from brick-red to yellow, but are frequently bicoloured, with the base of the lobes being reddish, and which merges gradually into yellow on the the apical half. O. wissmannii is quite distinct from Angolluma baldratii (now Orbea baldratii), with which it had been widely confused in collections, by the other hand there seems little doubt that the formerly Angolluma meintjesiana is conspecific with O. wissmannii.
Stems: Soft, erect or ascending, rooting from the bases, 4-angled, with soft- spinous projection at the angles. Surface smooth, light green, grey-green or dark green mottled with brownish or purple.
Flowers: The pedicellate flowers are borne singly or in pairs (rarely more) in short inflorescences. Star-shaped, about 20-25 cm in diameter. Corolla lobes narrow, almost linear, 12-20 mm long and more than 3 mm wide, strongly longitudinally folded back, glabrous or covered with short papillae, mostly brownish-red at the base and golden-yellow to bright-yellow towards their apex, but very variable in colour. Corona bright yellow 3-4 mm tall x 3-4 mm in diameter. Buds narrow.
Blooming season: This species produces numerous flowers simultaneously in late summer to autumn. Flowers exude a vague to intense smell of cat urine. This perfume attracts blow flies which are the natural pollinators. Following successful pollination of flowers pairs of seed horns are produced, packed with seeds attached to silky parachutes.
Subspecies, varieties, forms and cultivars of plants belonging to the Orbea wissmannii group
- Caralluma meintjesiana Lavranos: (= Orbea wissmannii) Flowers are fleshy stars with 5 narrow, linear lobes, mostly light green with a blood red centre but very variable. Distribution: Saudi Arabia, Yemen, Oman.
- Orbea wissmannii (O.Schwartz) Bruyns: Corolla lobes 12-20 mm long and more than 3 mm wide, strongly curved to touch each other behind lobe and lobes convex adaxially; yellow more or less suffused with red or red becoming paler toward apex, glabrous or covered with short papillae; corona 3-4 mm tall x 3-4 mm in diameter.
- Orbea wissmannii var. eremastrum (O.Schwartz) Bruyns: Corolla lobes 12-20 mm long and more than 3 mm wide, slightly folded back and lobes lightly convex adaxially; yellow suffused with red (sometime flesh-coloured) in proximal half, greenish yellow to yellow towards tip, glabrous or covered with short papillae; corona 3-4 mm tall x 3-4 mm in diameter.
- Orbea wissmannii var. parviloba Bruyns: Corolla lobes 9-10 mm long and less than 2 mm wide, pale yellow, covered with white hairs. Corona 1.5-2 mm tall,2.5 mm in diameter. Distribution: Yemen.
Bibliography: Major references and further lectures
1) Shaukat Ali Chaudhary, ʻAbd al-ʻAzīz ʻAbbās Juwayd, Markaz al-Waṭanī li-Abḥāth al-Zirāʻah wa-al-Miyāh (Saudi Arabia), Saudi Arabia. Wizārat al-Zirāʻah wa-al-Miyāh al-Markaz al-Waṭanī li-Abḥāth al-Zirāʻah wa-al-Miyāh, Wizārat al-Zirāʻah wa-al-Miyāh, al-Mamlakah al-ʻArabīyah al-Saʻūdīyah, “Vegetation of the Kingdom of Saudi Arabia” 1999
2) Sheila Collenette “An illustrated guide to the flowers of Saudi Arabia” Scorpion, 1985
3) John Hunter Thomas “Systematic Botany Monographs” American Society of Plant Taxonomists, 2002
4) S.A. Ghazanfar, M. Fisher “Vegetation of the Arabian Peninsula” Springer, 31/August/1998
Orbea wissmannii Photo by: Giuseppe Distefano
The gallery now contains thousands of pictures, however it is possible to do even more. We are, of course, seeking photos of species not yet shown in the gallery but not only that, we are also looking for better pictures than those already present. Read More...
Cultivation and Propagation: Orbea wismannii is an easy blooming plant when mature that require moderately watering through the growing season but enjoy plenty of water and some fertiliser in hot weather, this helps them to flower freely. Water more sparingly in winter according to temperatures. But, as with most asclepiads, it is unwise to leave them wet in cold weather. Winter care presents no problems at 5°C with plenty of light. Since roots are quite shallow, use a cactus mix or add extra perlite or pumice to regular soil potting soil. A gritty, very free-draining compost is suitable, and clay pots help the plants to dry out between watering.
Sun Exposure: Partial sun or light shade
Pest and diseases: Orbeas vary in their susceptibility to rotting, but are generally fairly easy to grow, especially if kept pest-free. They are very susceptible to stem and root mealy bugs, and damage from these may well initiate fungal attack. If you do have problems with a stem or with basal rotting, you can reliably isolate the healthy parts, dry them off, and re-root them in moist compost.
Cultural Practices: Re-pot every 2 years
Propagation: Easiest with stem cuttings. Allow cuttings to dry a day before planting. Stems must be laid (Not buried) on gritty compost and will then root from the underside of the stems. It can also be increased from seeds sowing in spring in moist, sandy peat moss.
Potting medium: Since roots are quite shallow, use a cactus mix or add extra perlite or pumice to regular soil potting soil. A gritty, very free-draining compost is suitable, and clay pots help the plants to dry out between watering.
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